Experimental Cyclic Behaviour and Constitutive Modelling of Laser-Cladding-Produced Stainless-Clad Bimetallic Steels

Laser-cladding (LC) additive manufacturing is an efficient and cost-effective method of metal 3D printing for repairing and strengthening damaged steel structures, but limited data exist on the mechanical properties of LC-produced stainless-clad bimetallic steels formed after LC repair process, particularly under cyclic loading. To address this, coupons with four clad ratios, including Q355 substrate-only, LC sheet, and LC-produced stainless-clad bimetallic steels, are prepared. Tensile and cyclic loading tests are conducted on these coupons, and their monotonic and hysteretic behavior, as well as failure characteristics, are analyzed. Test results reveal that the monotonic tensile stress-strain curves of LC-produced stainless-clad bimetallic steels exhibit no obvious yield plateau, with monotonic properties and cyclic hardening levels between those of the LC sheet and substrate. Moreover, the cyclic backbones of the bimetallic steels display significantly higher stress levels compared to the monotonic tensile curves, indicating substantial cyclic hardening. Both isotropic and kinematic hardening are observed, demonstrating a combined hardening response. The influences of loading protocol type on cyclic behaviour are also discussed. The cyclic backbones can be accurately described using the Ramberg-Osgood (R-O) model. The Chaboche plastic constitutive model, calibrated with experimental data, is used to simulate the cyclic behavior of the coupons in ABAQUS finite element (FE) analysis. The results show excellent agreement with experimental data, validating the model's accuracy in predicting the cyclic responses of LC-produced stainless-clad bimetallic steels. This research provides fundamental insights essential for the accurate analysis of structures repaired and strengthened using LC-produced stainless-clad bimetallic steels under seismic actions.